<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
</head>

<body>

<style type="text/css">
.testb:before {
    content: "";
    position: absolute;
    z-index: -1;
    top: 0px;
    right: 0px;
    bottom: 0px;
    left: 0px;
    border: 1px solid #3d91cf;
}
</style>

<div style="width:100px; height:30px; position:relative; margin:5px;" class="testb"></div>

<script type="text/javascript">

var enumerablesTest = { toString: 1, a : 5 }
for( var i in enumerablesTest ) { alert(i) } 
alert(enumerablesTest.hasOwnProperty('toString'))
</script>

</body>
</html>
